Lilla Irvine Leach (March 13, 1886 – September 10, 1980) was a botanist who spent most of her career studying plants in the Pacific Northwest and West Coast of the United States.

[1] Growing up on a farm helped Leach discover her love for flowers and other plant life by wandering around the vast natural settings.

During this time her husband John had finally won her over, leading the two to be quickly married on her parents' farm in an outdoor ceremony in 1913.

[2] Leach was awarded the inaugural Eloise Payne Luquer Medal by the Garden Clubs of America in 1950, and was named Portland Citizen of the Week in September 1945 for her war and conservation work.

[3] Lilla and John bought property in Southeast Portland on the Johnson Creek, where they built a small stone cabin, which they called Sleepy Hollow.